The invention relates to the field of sealed storage cells, particularly to the field of lithium-ion type storage cells.
The present invention relates to a method for sealing in a leak-proof manner an electrolyte filling orifice provided on a cell container wall by the use of a stopper arrangement. The invention also relates to a cell container with a filling orifice that is sealed off by this method.
A sealed storage cell or sealed electrochemical cell (these two terms being equivalent) comprises in a known manner a container accommodating an electrode plate group, which electrode plate group comprises an alternation of positive and negative electrodes flanking separators. The electrode plate group is impregnated with electrolyte. Each electrode is composed of a metal current collector carrying an electrochemically active material on at least one of its faces. The electrode is electrically connected to a power output terminal which ensures electrical continuity between the electrode and an external application with which the storage cell is associated. The electrode plate group is disposed inside the container, closed in a leak-proof manner by a cover. During manufacture of the container, provision is generally made to fill the latter with electrolyte through an orifice provided in the container wall. After filling, it is necessary to seal off this orifice in leak-proof manner.
Indeed, one of the container's functions is to prevent all leakage of electrolyte or material that might escape from the storage cell which thus could spread to the area around the cell. The electrolyte may be acid in the case of lead-acid storage cells or be a strong base such as KOH, LiOH or NaOH in the case of alkaline storage cells. This will be an organic solvent in the case of a Li-Ion cell. In order to avoid the space surrounding the cell becoming contaminated, it is therefore necessary for the container to be liquid-tight and that the electrolyte filling orifice be fully closed.